1. Field of the Invention
Example embodiments of the present invention relate to a semiconductor memory device. More particularly, example embodiments of the present invention relate to a temperature sensor instruction signal generator for a temperature sensor, and a semiconductor memory device having the temperature sensor instruction signal generator.
2. Description of the Related Art
In a semiconductor memory device, for example a DRAM, over time, stored data in a cell may be lost due to automatic discharge of the cell. The stored data may be recovered in response to a control signal of a controller. The recovery of the data may consume a specific amount of current even if the DRAM is not in operation, and such a recovery process is generally known as a refresh operation.
A temperature of a semiconductor memory device may increase due to both heat applied from devices surrounding the semiconductor memory device and/or heat generated by a refresh operation. The automatic discharge in the semiconductor memory device may be due to leakage current, and the discharge may also be related to the temperature of the semiconductor memory device.
As discussed above, a refresh operation may be required to restore the data, and the amount of leakage current should be taken into consideration for the refresh operation. The temperature of the semiconductor memory device may substantially influence the refresh period.
Although a temperature sensor may be embedded into a semiconductor memory device to measure (for example, directly) the temperature of the semiconductor memory, a specific amount of current may be consumed during the temperature reading. The operation of the temperature sensor may produce a counter effect, because the temperature sensor may consume additional current.